The invention relates to a process of packaging products, particularly foods and a closed container with packed products, particularly foods, which container with packed products has been subjected to a heat treatment after packaging.
Such a process and closed container are known in the art. The heat treatment, which consists, for example of pasteurising or sterilising, is to give a longer shelf life to perishable foods.
In the heat treatment of foods in a sealed package or container the pressure will, however, in general rise in the package so that the package may be damaged.
In order to prevent this, the package or container is usually made of pressure-resistant material, which is resistant to pressure increases, for example metal glass or a thick-walled plastic, or provision is made in the package or container for expansion features which absorb the pressure increase. However, this unfortunately leads to relatively expensive packages or containers.
Damage to the package or container is also avoided by increasing the pressure on the outerside of the package or container during the heat treatment, but this possibility is applicable only in a limited number of cases and, besides, it requires special features.